Humans have applied scents and fragrances to their skin since antiquity. Originally these aesthetically pleasing materials were commonly isolated in raw form as resins, gums or essential oils from natural sources, inter alia, the bark, roots, leaves and fruit of indigenous plants. These resins, gums, and oils were directly applied to the body or diluted with water or other solvent, including in some cases, wine. With the advent of modern chemistry, individual components responsible for the odor properties of these resins, gums and oils were isolated and subsequently characterized. Aside from common “perfume vehicles” inter alia, fine perfumes, colognes, eau de toilettes, and after-shave lotions, a wide variety of personal care or personal hygiene items also deliver for aesthetic reasons fragrance notes, accords, or fragrance “characteristics”.
It is well known that mixtures of perfume or fragrance raw materials when deposited on the skin lose intensity and may change character with time, mainly due to factors such as differential evaporation and skin penetration. Many attempts have been made to minimize these drawbacks, but so far without notable success. Particularly, efforts have been made to prolong the diffusion, as well as to improve other characteristics of fragrance materials, by e.g. increasing the fragrance raw material concentration or by using additives such as silicones, glycerol, polyethylene glycols and so on. Such additions, however, have never been adequate to increase the longevity of the fragrance odor.
Recently the advent of pro-fragrance and pro-accords have afforded the fine fragrance and perfume formulator with the ability to deliver fragrance raw materials to human skin in a controllable manner thus enhancing the longevity of the fragrance. Most pro-accords inter alia orthoesters, are suitable for delivery of fragrance raw material alcohols and esters. Aldehydes and ketones have been delivered via acetals and ketals respectively, however, both of these pro-fragrance materials depend upon the modification of the carbonyl moiety and the rate of ketone fragrance raw material release has been difficult to fine tune to the subtleties of fine fragrance and perfume accords.
Accordingly, there remains a need in the art for a fragrance delivery system which is capable of delivering aldehyde and ketone fragrance raw material releasing pro-fragrance which can be formulated into fine fragrances, perfumes, personal care and personal hygiene products wherein the aldehyde and ketone fragrance raw material components can be released in a highly controllable manner to provide enhanced fragrance longevity.